Screw-anchor.



S. H. FLEMIN".

SCREW ANCHOR.

APPLICATION FILED AUG 3, 1910.

Patented Oct. 10, 1911.

Toguli whom it may concern:

J'esidcnt of (hit-ago. county of (look. and

' formed of a coiled strip of soft metal. such wound upon a cylindricalforming rod;

' preferably project heyond the exterior sur- "UNITED STATES PA1*ENTOmen;

Application filed August 3,

lie it known that T. Srnrnnx ll. FLEM- ixo. a citizen of the UnitedStates. and a- State of l llitmls. have invented certain new and usefulImprovements in Screw-Anchors. of which the following is a full, clear.and exact description.

The invention relates to anchors for securing screws within socketsformed in lHitlt work. cement. stone or t'hc'likc. and seeks to providea simple and etl'ective (01b struction which can he economically made inlarge quantities. i a

The invention consists in the features of improvement hereinafter setforth. illustrated in the preferretlform in the. accompanying drawings"and more. part.icularl pointed out in the appended claims.

In the dr.-nvings. Figure l is a view in elevation of the improved screwanc hor. Fig. 2 a cross section thereof on the line 2-2 of Fig. 1. Fig.3 is a ltmgitudinal section on the line 33 of Fig. 2. Fig. 4 is a viewpartially in elevation and partiallyin section of a modified form. Fig.5 is a longitudinal sectional view of the anchor shown in operativeposition for holding a screw within its socket. Fig. 6 is a section onan enlarged scale on the line 6G of Fig. 5.

i The improved anchor comprises a sleeve as lead 0' an alloy of lead andtin or the like. The soft metal strip (1- is preferal'tly of rectangularcross section and is coiled or The cylindrical coil or sleeve thusformed can be readily and economically manufactured andthen cut intopieces or lengths to form the separate screw anchors.

The coils of the anchor sleeves preferably abut against one another (seeFigs. 1, 2, 3 and 4) and longitudinally extended stay pieces I) areprovided for sustaining the coils in proper relative position. Thesestay pieces are formed of hrass or like metal and are provided withinwardly ii-ejecting teeth 0 which are forced into the coils of the softmetal strip a, as indicated in l igs. l. 2 and These strips extendlongitudinally upon the exterior of the anchor sleeve and face, asmost-clearly shown in Fig. 2. Two of these strips are shown in the formillus- Specification of Letters Patent.

I rammed Oct. 1oQtfsii1. 191 0. set-taint). 575 367. .-f

tratcd. but more may he used aif nec or (lt.\'lI'tll)l(-' a Thethickness of the wall ofthe sleeve or am-hor.--tltatis to say. thethicln'tcss'of the" soft metal strip from which the sleeve" or anchor isformed. should preferably ll( slight]; greater than the depth ,nf;;thethread of thescrew for which illt tttlt' lltil' is designed, it beingunderstoml. ofleourse." t hat-the improved anchor'is niade in differentsizes in aecordahce with the different sizes of screws. The interiordiameter. of the sleeve or-anchor is prefei'ahly slightly. less than theshank or barrel of anemia for which it. is designed. Thefcoil is. wound.in the directionofthe thread of tlie st -rt. w

which is,. of coursesusuallyin righthand direction. In usingthefnnproved anchor, a.sui.tal le hole or socket is formed in the hrick, -s t:onc.

cement or the like. and the anchor. placed therein with its inner end inengagement with the bottom of the hole or soeketg: The sharp end a ofthe stripat the. inner. end of the sleeve orzanchor catches on the-hob.tom of the socket; and,- as, the screw is threaded into the outer endofthe sleevetlfc coils of the latter tend to unwind a-nd*thus expandintohindingcontact with -the=,-wall of the hole or socket. even thoughthe-latter is somewhat. largerthan the "anchor 'slecve. As the screw isdriven .into the sleeve. it expands the latter-and its threads readilycut into the soft metal body ofJ-the coils; At the same time, the staypieces 7) are driven into the sleeve, so that thev tend to rupture thelatter along longit-ut'linal lines. as indicated in Fig. (3. and thus't-ierm'it the further expansion of the soft metal body .-.f the sleeveor coiled strip into-lli'n'ding contact with the walls of the hole tdtherein the socket. w

The coils of the strip ((Wliittliftiiht the sleeve or anchor audthcteeth 0 of the stay pieces I) need have no particular relation to the.threads of the screw." T hose threads emhed themselves in the soft metalbody of by firmly secure the anchor and screw,withvthe sleeve and?interlock in an irregular fashion with the teeth 1 of the stay pieces.The. stay pieces I) having the teeth c should too he formedof metalwhich is considerably tougher than thesoft metal strip a. The latter. asstated, is formed of lead or lead alloy. or the like. The stay piecesare prefreadily driven into the hole or. socket formed to receive thesame. As theserew is driven in it expands the soft metal body, asdescribed, and the shank or barrel of the screw will bear upon the endsof the teeth 0 position.

and force the stay pieces b into firmbind ing contact with the walls ofthe hole or, socket to further aid in holding the anchor screw inposition. The threads of the screw -will' not be broken by contactingwith the teeth 0, but the latter will be bent or defiected by thethreads. Moreover, the ir regular interlocking of the threads and teethwill further aid in holding the screw in By forming the sleeve of acoiled-strip of soft metal the coils are separately expansi ble, so thatthey will readily conform to the opening for the'screw in spite ofirregularities therein. The coils will thus be expanded into firmbinding contact with all portions of the wall of the screw opening, eventhough this 0 ening may not be uniform throughout.

.urthermore, inasmuch asthe coilslare formed of a softmetal stri theyneed; 0t and preferably do not con orm to beiiigcut in the coils as'thescrew is threaded into the sleeve, Furthermore, inasmuch asthe sleeveformed of a number of coils is readily expansible, the bore of thesleeve can be quite small, as compared to the shank of the screw withwhich-1t is used; without increasing the difiicultypf threading thescrew into position. For this. reason the v coiled anchor can not onlybe readily forced 1nto snugbinding contact with the wallsof the screwopening, but will also snugly engage the shank and tlireads of thescrew.

While the cylindrical form illustrated in Figs. 1, 3 and 5 is deemedpreferable on account of economy in manufacture, the anchor may be'madein conical form, as shown in Fig. 4. It is also obvious that theparticular details set forth maybe varied without departure from theessentials of the invention, as defined in the claims.

I claim as my invention p 1. A screw anchor comprising a cylindrical,expansible sleeve form diameter formed of a'=coi1ed, soft metal.

strip, the coils of said sleevebeingadafited j to be separately expandedsnug binding contact with the wall of 'the'ppening for't he screw and tobe indented by the threads of.

the screw, substantially as described.

2. A. screw anchor comprising a 'cylins, '1

'drical, expansible sleeve of substantially 'an form diameter throughoutand havin internal diameter less than that of the s ank of the screw'for which itis designed, said sleeve being formed of a .coile'dsoftmetal strip of substantially rectangular-cross-section, the coils'ofsaid strip being in contact and adapted 'tobe expanded and indented bythe threads of the screw, substantially as described. p

3. A screw anchorcomprising a cylindrical, expansibl'e' sleeve formed ofa coiled, soft'metal strip anda strengthening stay for the sleeveextending lengthwise thereof.

4. A screw anchor comprising an expansi ble sleeve formed of a coiledstrip of soft metal and stay pieces extending lengthwise substantiallyas described. the; reads ofthe screw, the female :thread 6. A screwanchor comprising an expansible sleeve formed of a coiled "strip of softmetal and longitudinally extending stay pieces having inwardlyprojecting teeth indenting the coils, substantially as described.

7. A screw anchor comprising a cylindrical, expanslble sleeve formed ofa CQllBd, soft metal strip of rectangular section and stay .piecesextending longitudinally upon pieces of brass having inwardly projectingteeth indenting the coils, substantially as described.

- STEPHEN H. FLEMING.

Witnesses ELEANOR H. HAGENOW, KATHARINE GERLACH.

